61.7k views
0 votes
Suppose we want to choose 4 objects, without replacement, from 17 distinct objects. (a) If the order of the choices matters, how many ways can this be done? (b) If the order of the choices does not matter, how many ways can this be done?​

1 Answer

2 votes

(a) If the order of the choices matters, this is a permutation problem. We want to choose 4 objects from 17 distinct objects without replacement. The number of ways to do this can be calculated using the formula for permutations:

P(n, r) = n! / (n - r)!

where n is the total number of objects and r is the number of objects to be chosen.

In this case, we have 17 objects and we want to choose 4, so the number of ways is:

P(17, 4) = 17! / (17 - 4)! = 17! / 13! = 17 × 16 × 15 × 14 = 43,680.

Therefore, there are 43,680 ways to choose 4 objects without replacement if the order of the choices matters.

(b) If the order of the choices does not matter, this is a combination problem. We want to choose 4 objects from 17 distinct objects without replacement. The number of ways to do this can be calculated using the formula for combinations:

C(n, r) = n! / (r! * (n - r)!)

In this case, we have 17 objects and we want to choose 4, so the number of ways is:

C(17, 4) = 17! / (4! * (17 - 4)!) = 17! / (4! * 13!) = (17 × 16 × 15 × 14) / (4 × 3 × 2 × 1) = 2380.

Therefore, there are 2380 ways to choose 4 objects without replacement if the order of the choices does not matter.

User Tommy Lee
by
8.1k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.